72 454 exhaust french locks

[Randall K.]

Anyone know where I can get these - preferably in stainless?

Thanks in advance.
Randy

[Terry M.]

Re: 72 454 exhaust french locks

Anyone know where I can get these - preferably in stainless?

Thanks in advance.
Randy

I do not believe big blocks used french locks after mid-1969, however, if you want them I would try Paragon or any of the big box Corvette stores. I know they sell stainless steel french locks for small blocks, and except for the lack of demand, I can't imagine they would discriminate against any engine that needs seven fasteners to hold a rocker cover on.

[Randall K.]

Re: 72 454 exhaust french locks

Hmmm... I was under the impression that they probably did based on a post from Joe Lucia as https://www.forums.ncrs.org/showthre...50735&uid=1990.

Given that, I had already searched a lot of the on-line stores with no luck with the exception of Doc Rebuild page 187. Thought it was a little strange that I would only find these in 1 place.

Thanks
Randy

[Terry M.]

Re: 72 454 exhaust french locks

Hmmm... I was under the impression that they probably did based on a post from Joe Lucia as https://www.forums.ncrs.org/showthre...50735&uid=1990.

Given that, I had already searched a lot of the on-line stores with no luck with the exception of Doc Rebuild page 187. Thought it was a little strange that I would only find these in 1 place.

Thanks
Randy

I didn't realize they quit using that funky bolt Joe talks so much about. I must had missed his post you cite, but I am not used to seeing french locks on large motors after 1969. I'll ding up some of the current engine compartment judges and hope they chime in here. Perhaps my recollections are faulty -- it wouldn't be the first time, nor the last I suspect.

[Joe L.]

Re: 72 454 exhaust french locks

I didn't realize they quit using that funky bolt Joe talks so much about. I must had missed his post you cite, but I am not used to seeing french locks on large motors after 1969. I'll ding up some of the current engine compartment judges and hope they chime in here. Perhaps my recollections are faulty -- it wouldn't be the first time, nor the last I suspect.

Terry------


OFFICIALLY, I don't think they did quit using the prevailing torque bolt. OFFICIALLY, I think it was used for all late 1967-74. However, what I'm less sure about is what was ACTUALLY used. My information regarding usage and non-usage of french locks or prevailing torque bolt provided in the aforementioned linked thread was pretty much "interpolation" and not necessarily 100% accurate.

OFFICIALLY= "according to GM"

[Terry M.]

Re: 72 454 exhaust french locks

Terry------


OFFICIALLY, I don't think they did quit using the prevailing torque bolt. OFFICIALLY, I think it was used for all late 1967-74. However, what I'm less sure about is what was ACTUALLY used. My information regarding usage and non-usage of french locks or prevailing torque bolt provided in the aforementioned linked thread was pretty much "interpolation" and not necessarily 100% accurate.

OFFICIALLY= "according to GM"

Well now I have something else to look at Mark IVs for besides dipsticks.

[Kenn S.]

Re: 72 454 exhaust french locks

... However, what I'm less sure about is what was ACTUALLY used.

My '70 has no french locks, and I'm reasonably certain it's unmolested in that regard (never had the manifolds removed).

[Mark D.]

Re: 72 454 exhaust french locks

I would not expect to see frenck locks on big motor Corvettes from (including) 68 through 72. I would expect the torque bolts on the outer most attaching points on each side of the motor for a total of 8.
I deduct for the locks and also for the lack of the 'funky' bolts.

[Dick W.]

Re: 72 454 exhaust french locks

NO french locks on '72 big blocks. Any source that shows that application is incorrect.

[Gary B.]

Re: 72 454 exhaust french locks

I also would not expect to see a 72 with french locks. I would expect shouldered bolts on the front two and rear two attachments bolts, with regular hex on center four bolts. Picture is from a low mileage 71. 8800 mile car.
Gary

[Randall K.]

Re: 72 454 exhaust french locks

Thank you to all who replied. I now know what to replace on my manifolds.

Randy

[James B.]

Re: 72 454 exhaust french locks

NO french locks on '72 big blocks. Any source that shows that application is incorrect.

I agree. No french locks are on my '72 454.

[Kenn S.]

Re: 72 454 exhaust french locks

Now you have me curious as to what these "funky bolts" look like. The 454 is shoehorned in there, and my car has air making it worse, so I don't see anything strange from above the engine. Not a good enough vantage point. But when I get it out of the car, I'll be interested to see what they look like.

Am I to assume a 6-point socket won't get them out? Use a 12-point socket, like with a rag joint? Or is there some "funky bolt socket" I need?

[Joe L.]

Re: 72 454 exhaust french locks

Now you have me curious as to what these "funky bolts" look like. The 454 is shoehorned in there, and my car has air making it worse, so I don't see anything strange from above the engine. Not a good enough vantage point. But when I get it out of the car, I'll be interested to see what they look like.

Am I to assume a 6-point socket won't get them out? Use a 12-point socket, like with a rag joint? Or is there some "funky bolt socket" I need?

Kenn-----


A 6 point socket will work just fine on these prevailing torque bolts.

[Terry M.]

Re: 72 454 exhaust french locks

Now you have me curious as to what these "funky bolts" look like. The 454 is shoehorned in there, and my car has air making it worse, so I don't see anything strange from above the engine. Not a good enough vantage point. But when I get it out of the car, I'll be interested to see what they look like.

Am I to assume a 6-point socket won't get them out? Use a 12-point socket, like with a rag joint? Or is there some "funky bolt socket" I need?

Kenn -- Unless you pull the end four bolts out you won't see too much "funk." The heads are untrimmed (I will bet the censor bot changes most of this word to asterisks. I am trying to say unt r i m m e d) or as we sometimes call it recessed hex -- with a built in washer. The threaded shaft of the bolt is not round, but is tri-lobed shaped. Kind of like a three leaf shamrock in cross section. It deforms the threads in the head as it is driven in and thus resists withdrawal (I am not sure why the censor bot doesn't asterisks that word, but maybe it is just me).